OPINION:
Let's get one thing straight: John Key has just called a snap-election – albeit in slow motion. The prime minister's threadbare excuses notwithstanding, there is absolutely no valid constitutional reason why New Zealanders should be trooping to the polling booths 70 days early.

There have been no defections from the National Party's coalition: the Government is in no danger of losing its majority on the floor of the House of Representatives. Neither has Mr Key's caucus dissolved in bitter acrimony. Nor has a vital component of the Government's legislative programme been defeated in a parliamentary vote.

So, why aren't we going to the polls on the last Saturday in November – as we have done for most of this country's post-war history?

The answer is as simple and straightforward as it is brutal and self-serving: because holding the election two months early offers National a huge political advantage.

Mr Key has examined the political entrails and determined that the longer he delays the election the higher the probability that the parties of the Left will attain sufficient political momentum to unseat his government.

By bringing the election forward he is hoping to deny Labour and the Greens the full electoral effect of rising mortgage interest rates and electricity prices. Labour-Green policy on both issues offers the voters considerable relief. The less time people are given to work that out, the better it is for the Government.

Mr Key and his strategists were also aware that Labour was pinning its hopes for victory on persuading a quarter of the 800,000 people who abstained from voting in 2011 to cast a vote in 2014. Logistically-speaking, that was a huge ask – especially for a political party woefully short of both experienced election workers and the funds required to make them effective.

National's strategy team clearly decided to deprive their opponents of two months worth of crucial training and fundraising time. Viewed realistically, the scale of this curtailment has almost certainly torpedoed Labour's main election strategy. If there's a Plan B at the back of Matt McCarten's cupboard, now would be a very good time to dust it off.

The other tactical advantage of going two months early is the hugely disruptive effect Mr Key's announcement is bound to inflict on Labour's campaign timetable. Budgets will have to be redrawn, advertising space and air-time reconsidered, policy finalised faster, travel schedules re-worked, fundraising efforts intensified.

While this is unlikely to produce panic in Labour's ranks, it will bring down what soldiers call "the fog of war" and all its attendant evils: inadequate information; impaired decision-making; unnecessary and morale-sapping losses and defeats.

These would be big enough problems in a tightly-run and fiercely united political party – but in a party riven by the most bitter factional in-fighting, they'll likely prove catastrophic. Public disunity in the midst of an election campaign (and that's precisely where we all are) would not only make a Labour victory inconceivable but, by making National's victory appear inevitable, it could also have a devastating effect on turnout.

It is here that the sheer mendacity of National's strategy shines forth in all its Machiavellian brilliance.

If Labour's voters, seeing no hope of victory, decide to stay at home, and the participation rate of eligible voters drops even further than it did in the record low turnout of 2011, then with just a few thousand more votes than they received last time it is entirely feasible for National to win an outright (ie 50 per cent + 1) election victory.

This is where the slow-motion aspect of National's snap-election strategy kicks in. The more frenetic, disorganised and disunited Labour appears; the cooler, calmer and more collected the National Government is bound to appear by contrast.

To win, Mr Key has only to appear pleasantly prime-ministerial. Making the most of his photo opportunities and taking great care to project the image of a leader who knows exactly what he's doing.